The field of the invention is chairs and couches provided with a movable back support and with a seat which is pivotably displaceable about a horizontal axle supported in a base. Such chairs are known per se. In one of the known embodiments a coupling between the carrier of the seating surface and the carrier of the backrest or its extension is present in such a manner, that the movements of the backrest cause positively a determined movement of the seating surface, and conversely. Therefore, the usability of said known chairs is limited.